Driven by growing pressure to lower cost and to shrink physical volume, various microstrip antennas for antenna-in-package designs (“AiP”) have been developed in the past few years for portable wireless radio transceivers. These include AiP designs:                (a) suitable for multi-chip solutions for wireless radio transceivers;        (b) with both active and parasite microstrip patch antennas suitable for multi-chip solutions for wireless radio transceivers;        (c) with a microstrip patch antenna suitable for multi-chip solutions for wireless radio transceivers;        (d) with a microstrip patch antenna suitable for single-chip solutions for wireless radio transceivers;        (e) using an inverted-F antenna suitable for multi-chip solutions for wireless radio transceivers; and        (f) using an inverted-F antenna for multi-chip solutions for wireless radio transceivers.        
The existing AiP designs have serious drawbacks:                (1) AiP designs using microstrip patch antennas can have fractures and warping if they are implemented in low temperature, co-fired ceramic (“LTCC”) technology;        (2) AiP designs using inverted-F antennas have to two-dimensionally integrate with multi-chip radios. As such they need a larger footprint on printed circuit boards (“PCB”); and        (3) they are designed for single-ended signal operation requiring complex conversion circuits to link to highly-integrated radios where differential signal operation is preferred.        